Pressure reduction chamber and unloading valve for explosives



s. M ZANDMER 2,504,611 PRESSURE REDUCTION CHAMBER .AND UNLOADING VALVE FOR EXPLOSIVES 2 Sheets-Sheet 1 INVENTOR. Sou: MYRON ZmvnmER. 3' BY 477'ToRA/EY5.

April 18, 1950 Filed Feb. 25, 1946 Apnl 18, 1950 s. M. ZANDMER PRESSURE REDUCTION CHAMBER AND UNLOADING VALVE FOR EXPLOSIVES 2 Sheets-Sheet 2 Filed Feb. 25, 1946 INVENTOR. Sous Mme/v Zn/wm-R.

mum

HTTORA/E vs.

Patented Apr. 18, 195i} OFFICE PRESSURE REDUCTION CHAIVIBER AND UNLOADING VALVE FOR EXPLOSIV ES Solis Myron Zandmer, Los Angeles, Calif.

Application February 25, 1946, Serial No. 649,850

This invention relates to the art of regulating the displacement and detonation of liquid explosive in Wells, and more especially to a pressure reduction chamber and unloading valve for liquid explosives in oil and gaswells which have been prepared for the same.

The present invention is for improved apparatus in connection with means and a method of treating oil and gas wells by the introduction of a liquid explosive and the detonating of the explosive in the oil or gas bearing fissure systern of producing strata and covers apparatus which is an improvement over that shown in my co-pending applications, Serial No. 557,100, filed October 4, 1944, and Serial No. 560,565, filed October 27, 1944, now abandoned.

In my'prior applications referred to, I disclosed methods and means for introducing a quantity of a liquid explosive, such as nitroglycerine, into a prepared wellby displacing a column of a nonexplosive' fluid, such as water, mud or the like, by a quantity of liquid explosive, and, upon the liquid explosive being placed in with the well tubing or well casing, as the case may be, opening a bottom hole valve and causing the liquid explosive to be moved into the fissure system of the strata and thereafter detonating the explosive to enlarge the fissure system.

The successful method which has been achieved by my present invention of depositing the liquid explosive into the fissure system has required the development of certain techniques wherein the liquid explosive is carried to the bottom of the well and then transferred to the fissure system.

This transition step requires the displacement of the water or mud column in the interstitial spaces of the column of turbulence by the liquid explosive and thereafter accelerating and displacing the liquid explosive by movement into the strata. This starting movement or acceleration must be accomplished without any shock, jolting or vibration, which would cause a detonation of the explosive at the time its motion is started or before it has .been substantially transferred to the formation, and is accomplished by my present invention by the herein disclosed pressure reduction chamber and unloading valve,whereby the pressure on the liquid explosive, due to its own column and the column of inert liquid thereabove, is reduced to a pressure which is above the reservoir fluid pressure to permit the liquid explosive to flow into the formation, and this change in pressure is effected gradually and withoutshock.

9 Claims. (Cl. 10222) The pressure reduction chamber and unloading valve of this invention comprise essentially a cylinder secured to the loading pipe or tubing, if the tubing method is employed, or positioned in the well casing itself substantially at or slightly above the level of the producing strata, and having an upper inlet and a lower outlet, the outlet being controlled by a suitable valve which may be a piston valve. If the latter, the piston valve may include a hydraulic jack or dash-pot feature which is moved slowly to a position to open the outlet to release the liquid explosive held above the piston, the movement of the piston being initiated by the application of fluid pressure higher than that of the hydrostatic pressure of the column of fluid, which could be sustained by the shear pins without-this additional fluid.

Immediately above'the piston I provide a turbulence chamber or chambers which may include spaced plates or similar elements which provide small orifices, pipes-or other openings, or may comprise straight or curved tubes of any type or shape, in the nature of a filter to resist the movement of the liquid explosive therein and thereabove so that the fluid movement is restricted and the fluid pressure is reduced before reaching the outlet port or ports. The turbulence chamber or pressure reduction chamber may include a plurality of pellets, such as spheres, agates, marbles or the equivalent, forming interstitial spaces which restrict the fluid flow to the desired and necessary rate.

With the foregoing general purpose and objective contemplated, the invention can be best understood by the more specific description thereof considered with reference to the accompanying drawings, wherein:

Figure 1 is an elevation view of a pressure reduction chamber and unloading valve embodying a form of my invention.

' Figure 2 is an enlarged partial sectional view of the same, the section being. taken along the line 2-2 of Figure 1.

Figure 31is a sectional view taken along the line 33 (if-Figure Lshowing the plunger valve prior to movement to outlet opening position.

Figure 4 is a view similar to Figure 3, showing the valve after movement to outlet opening position.

, Figure 5 is a fragmentary enlarged view showing the lower end of the pilot tube shown in the other figures.

Figure 6 is an enlarged sectional view taken along the line 54 of Figure 3.

Referring more particularly to the drawings, I show a well bore It extending vertically into an oil or gas bearing stratum l2 having a fissure system Hi in communication with bore Hi. The well is shown as having a casing l6 terminating at [8 immediately above the stratum I2.

I show and indicate by numeral 20 a pressure reduction chamber and unloading valve connect-- ed to a pipe or tube string 22 running to the top of the well and lowered or manipulated by the conventional derrick, not shown. Unit 20 comprises essentially a pipe section 24, a plurality of pipe sections 26 connected bylcollars' 28 \and'a pipe section 38 connected by 2,:0011a1f32 .to the adjacent section 26. Suitable packers 34! may be provided on pipe section 24, andslips36-may be similarly provided.

A plurality of plates 38 are providedand secured between pipe sections 26, as shown. A screen 39 may be provided on each plate 38 to prevent the pelletsfrom covering the'holes in the plate. The plates may be formed with small apertures to support-pellets to form a'turbulence chamber' provided by the interstitial spaces between the pellets, constituting restricted" flow passages therethrough.

Upper and lower chambers or other chambers may be filled with gravel 42 or other material which'will pack to a degree, and the'interstitial spaces therebetween maybe-initially filled with water, aquajell or similar material which -will notpermit "the liquid explosive to enter this chamber until'the bottom hole valve has been opened, but which will'thenpermit aflow thereof through the chamber. through reduction chamber 20, as-shown, and has a plug 46 =atthe bottom thereof as shown in Figure 5. Pipe sections 26 may be encased in cement sleeve 2'! or other outside tamping, if desired.

'Pipe section 30 is capped or plugged at the bottom at 48 and has one or more openings bll in a side wall portion thereof forming the discharge outlet for-thetunit. A pistonvalve 52 is positioned in section Stand has a -stem54 connected thereto and to a-plunger B. Plunger es has 'altubular passage 58-terminating withan opening as which communicates from the chamber 60, formed below the plungenand'the space thereabove which is in communication withuthe openings '50and thence to the fissure system is .pressureabove the piston valve to shear these pins when desired. One or more openings '66 may be provided ingpipe. section 30, which openings are covered .by plungerbfi, as -shown in' Figure" 3,

until the plungeris moved-to uncover -the open -ings, .to permit the .dashpot fluid 58,-belew the plunger to. escape after passing through passage 58 after piston. belles-passed below the lowermost of the outletjaperturesjfl.

. .In .the. operation of the i invention, unit 29 is lowered on tubing '22 to "the bottom of-the well ,bore-lt as shown.in.,Eigure..l,, and the tubing'-'22 either left in theiwellorremoved from above the packer, according to whether thetubingor cas- .ing .,method .described ,in my rne d ng app cations is used. The. ,unitgjextends substantially opposite the oil or gas bearing strata 'l2,"the

A-pilot tube ltextends 1 I without previously filling; the tubing: 22 with inert fluid or liquid. The pilot tubeM had been filled with explosive when it was first placed in the site.

carries is in position as above describedpthe ,fiuidhead tubing and the interstitial spaces formed by pe1- lets lfi and the gravel or equivalent material 42 was filled with inert fluid when these pellets or gravel were placed in each section of this chamber. When all of the explosive desired to be ultimatel displaced into the formation has been added to the tubing, or to the casing, if the tubing has been removed, a detonating device or godevil T9 is pushed down to the top of the explo- This go-devi has'a ball and seat float which allows the:go-devil to-be: pushed down .to the top of the explosion allowing theairito'escape from under it, until the .go-devilV-reaches the explosive; at which timewthev ball .floatgrises and closes so that the go-devil :cannotbemushed through the liquid explosive.

There is another ballabove thislfirstsball which closes or seats down :and does not let. fluid,- which is to ultimately drive the "go-devil and-theliquid explosive; fiow or pass through the go devil so that the go-devil now forms a solid piston between the top of the explosive-and :the driving fluid above it. 'Ifthe casing method is used, the go-devil will have the' same construction but will naturally be made to fit the casing rather than the. tubing, In either .-;case,:it- :can-beaso arranged that a given volume-1of .inert fluid, as water, can be placed on top-of-the liquid-explosive so that-the go-devil restson top of this fluid, the purpose in-these cases. being to have the upper portion of thecolumn of turbulence filled not with-explosive but with-inert fluid at the time the go-devil reaches-the top of the column.

When ready, that is-when the (go-devil which the contact exploder or fwar-head .ll

of the column is then increased, as by pumping, at the top 'of the well, which increase of -pressure will cause. pins 65. to shear ofirand permit the unloading valve, comprising-piston52 and plunger to move downward, uncovering. outlet openings 5G, and, permit the liquid explosive to fiowinto thefissure'system l2,: the movement of the piston being maintained at a slow rate while thedash-pot-fluid BBescapesthroughpassagefili and thencev out through zoutlet openings 55 or through-openings 6.6, when-the piston unit has moved tolowermost position, as shown in Figure l.

The liquid explosive thus-starts to move slowly downwardly,throu he.iilirbulfi fi Chamber without :shock, .jolting orv vibration,- which would otherwise .occur :if 11113921 cthe xshearingaoi pins as, the piston 52.scouldzinove.suddenly, or

if' there were {liquid explosive in .the gcolumn of turbulence-at that :time. ".The-. inert:.fluid.in the bottom ofthe column of: turbulencevis .under: the iull pressure of the column :when thepistenfiz is caused to move, and therefore, :when'this'fluid rushes out of :the holes 1 50, it is' shoc'ked by'the lence and its pressure is gradually broken in this chamberor column so that when it reaches the portholes there has been a gradual pressure reduction and no shock takes place. The damping piston 56 below pins 64 causes piston 52 to move so slowly as it gradually passes more and more apertures 50 so as to practically eliminate vibration, shock and hydraulic hammer of even the inert fluid.

When all of the liquid explosive is caused to pass out through outlet openings 59 into the fissures l4 and has thus been unloaded from the well, the detonating device or go-devil It strikes the gravel 4'2, which detonates the liquid explosive in the unit 20 and the fissure system, the explosion being conducted through pilot tube 44 to insure a rapid propagation of the explosion through the cylinders comprising the turbulence chambers.

This process has actualiy been gone through in a test well wherein 5,200-quarts of liquid explosive were displaced and exploded outside the bore in the exact manner described and the explosive was successfully handled without shock to cause a premature explosion. The pressure when shearing the pins G4 Was reduced, in this case,

from 3,700 pounds per square inch to the reservoir fluid pressure below the column of turbulence, which, in this case, was 673 pounds per square inch and the entire volume of liquid ex- .plosive was displaced through the column and into the formation. The detonating device or .go-=devil 10, upon reaching the topv of the column of turbulence, contacted the first material or substance in the chamber, which, in this case,

was gravel 42 and the contact exploder fired, by contact, and detonated the liquid explosive in the pilot tube 44 and the explosion conducted through the pilot tube insured a rapid propagation of the explosive through the remaining explosive in the lower portion of the column of turbulence and thence to the connected explosive flowing therefrom in the formation.

In this case, as long as there was a substantial column of explosion in the pilot tube to be detonated, it could detonate the explosive which had been displaced from the bore, even though said displaced explosive became separated from the bore by an inert fluid, which fluid could, by detonation of the explosive in the pilot tube, transmit the explosive shock to the displaced explosive and cause that explosive to be detonated as Well.

This principle of displacing explosive from the bore may well result in putting very large quantities out in similar manner and exploding these large volumes of explosive farther and farther from the bore as it is learned just how far away from the bore the inert driving fluid can set ed that explosive by transmitted shock.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom Within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and systems.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. Apparatus of the character described comprising a cylinder having an upper inlet and a lower outlet, means adapted to sustain a fluid column of unstable explosive above said outlet and adapted to be actuated by an increase in the fluid column pressure to open said outlet, and flow restricting means in said cylinder above said first means and a passage Icy-passing said flow restricting means for a portion of the column of explosive, said last means including a plurality of spaced plates, each having a plurality of openings of relatively small cross-section, said plates form ing turbulence chambers.

2. Apparatus of the character described comprising a cylinder having an upper inlet and a. lower outlet, means adapted to sustain a fluidi column of unstable explosive above said outletand adapted to be actuated by an increase in the fluid column pressure to open said outlet, andl flow restricting means in said cylinder above;- said first means and a passage by-passing said. flow restricting means for a portion of the column of explosive, said last means including aplurality of spaced plates, each having a plurality of openings of relatively small cross-sec-- tion, said plates forming turbulence chambers, and loose flow restricting material in said chambers.

3. Apparatus of the character described com prising a cylinder having an upper inlet and a lower outlet, impermeable means adapted to sustain a fluid column of unstable explosive above said outlet and adapted to be actuated by an increase in the fluid column pressure to open said outlet, and flow restricting means in said cylinder above said firstmeans and a passage by-passing said flow restricting means for a portion of the column of explosive, said last means including a plurality of spaced plates, each having a plurality of openings of relatively small cross-section, said plates forming turbulence chambers, and flow. retarding material in said chambers, said material comprising pellets dis posed to provide interstitial spaces therebetween.

4. Apparatus of the character described comprising a cylinder having an inlet and an outlet, means adapted to sustain-a fluid column of unstable explosive above said outlet and adapted to be actuated by an increase in the fluid column pressure to open said outlet, and flow restricting means in said cylinder above said first means and a passage by-passing said flow restricting means for a portion of the column of explosive, and having a lower end closure releasable upon said increase in fluid column pressure, said first means including a piston having dash-pot means adapted to regulate the rate of movement thereof when actuated by said fluid column pressure.

5. Apparatus of the character described comprising a cylinder having an inlet and an outlet, means adapted to sustain a fluid column of unstable explosive above said outlet and adapted to be actuated by an increase in the fluid column pressure to open said outlet, and flow restricting means in said cylinder above said first named means and a passage by-passing said flow restricting means for a portion of the column of explosive, and having a lower end closure releasable upon said increase in fluid column pressure, said first means including a piston having dashpot means adapted to regulate the movement thereof throughout the full extent thereof when actuated by said fluid column pressure, said dash-pot means comprising a cylinder, a fluid in said cylinder and a plunger in said cylinder having a restricted fluid escape passage.

6. An apparatus for loading an oil well with explosive fluid comprising a cylinder having an sepeiniset sea -s ie'eei sauet s flbiiv ontrol ans" ii-it'ialIy* cl6sing said lower' outlet V tsntiailynning the iiyiind -ediaceiit-tee -ibwewend' meresr and- S fiositi'ond with resfict to dzli' bottorii or the cyl- V i'de th'ereb'e'twen, Said g semen above said space ana -assess;--C imxni1ri1taengbetween said space and the recess'e'd ioortion, -a m'a'ss of substantially *solid rnateriai -in the space adapted kirbug h"Said p'aS'Sage, iempdmry' retaining means between said member and the" cyli er reieesaeie under firessur'e, -'flow "riiiibtihfifiafis in said cy1ihd'r-abUVe said menses-remiss, in ei'stitial ace, an'inert fluid 'in"the iotvei' portion of saw-space, and an unstable "-e'rfil'o'sive '-''in said cylinder located above'andsep said ine'rtfluid, said xiilosive iiuidi having access to sa'iid lovveropenmg renewin -rhe p ssage thereto of the inert fafter releas of said temlorary retaining "7. An assassins ion-loading -an -oilvs'lell vvith explosivefiuid comprising a cylinder having an a loti efoiitifia flow ccfitr'olvalve 1 let comprishe iylirider forming a ton element above and shaded on 451 ent 'foririing' a recess 'tiveen'said 's pa 'ce -and saidress and a substantially solid material in said space adapted- 126 "flow untier i$ressur e; temporary ietainiiig' in'eans "-seeufifig brie-of said bistori-elm'e'n-ts to the' 'cyliride'r,

tier above -the?"s'eiio'ntiipistrr element-'forming-interstitial space, an'- inert'fiuid' in'the lowerpottion of said space having access *to' saidlower opening on' release of "said temporary retaining means, and anunstabie' expl siv fl n s ylinder above and separate from said'i'nert fluid, and a ilot tube for explosive fluid bypassing the flow restricting means; said temporary retaining means being releasable under fluid pressure in th upper portion of "saidcylinder whereby said pressure is transferred to said'solid material for gradually pressing said piston elements to a position open ing said lower outlet.

9. An apparatus for leading an oil Well with explosive fluid comprising a' cylinder having an upper inlet and" a lowe1"-"0utlet of progressively increasing flow capacity, a fl'ow control valve means initially closing said lower outlet comprising a piston element in the cylinder above the bot-- tom of said eynnner forming a spa'ceb'etwe'enitself and the bottom, asecb'hd piston element above and spaced from the "first piston element formirig a recess the'rebetween having'a'c'cess to said lower outlet, a, mas's'of substantially solidfl'owable material inthespae"adapted'to fiow under 'pres sure, means forming 'a restrictedpassage between said space and said recess for said material, shear pins securing said second pistoneleme'nt 'to' the cylinder, f nely divided flow restricting means Y in said cylinder above thesecond piston element forming interstitial s ace, anin'ert fluid in the lower portion of said space, an*'uIista-ble explosive fluid in said cylinder above and separate from said inert fluid, and a pilot tube for explosive fluid bypassing the'fiow restricting means and communicating at the-lower' end' with said second piston element and-at the upper-endwith "the interior of said cylinder above the flow'restrictifig means, said pins being shear'abl e under pressure of fluid above said -second"piston 'elem'e'ht whereby said piston elements move downwardly-at a rate retarded by flow of said material through the restricted "passage 'mea'ns'to a position wherein said lower outlet is adapted to"succ'essive'l receive thein'ert 'fiuidand the'eiiplosive fiuid' ata progressively increasing rate.

SOLIS MYRON ZANDMER.

"REFERENCES CITED The following references-are of recordin tli'e file of thisbaitrit:

UNITED STATES PATENTS 

